Light-emitting devices using light-emitting diode elements (LEDs) are widely used. An old-type light-emitting device has a structure shown in FIG. 8. More specifically, an LED 33 is bonded to a substrate 31 through a die-bonding adhesive 32, and a p electrode 34 and an n electrode 35 on the upper surface of the LED 33 are wire-bonded to connection terminals 36 of the substrate 31 through gold wires 37. The entire LED 33 is sealed with a transparent molding resin 38. However, in the light-emitting device shown in FIG. 7, light having a wavelength of 400 to 500 nm and contained in the light emitted from the LED 33 to the upper surface side is absorbed by the gold wires, and part of the light emitted to the lower surface side is absorbed by the die-bonding adhesive 32. This causes a problem in that the light emission efficiency of the LED 33 is reduced.
In view of the above, Patent Literature 1 proposes flip-chip mounting of an LED 33, as shown in FIG. 7. In this flip-chip mounting technology, bumps 39 are formed on a p electrode 34 and an n electrode 35, and a light reflecting layer 40 is provided on the bump-formed surface of the LED 33 so as to be insulated from the p electrode 34 and the n electrode 35. The LED 33 and a substrate 31 are connected to each other using an anisotropic conductive paste 41 and secured to each other by curing the paste 41. Therefore, in the light-emitting device in FIG. 7, the light emitted upward from the LED 33 is not absorbed by gold wires, and most of the light emitted downward from the LED 33 is reflected by the light reflecting layer 40 and then emitted upward, so that light emission efficiency (light extraction efficiency) is not reduced. A paste prepared by dispersing conductive particles in a thermosetting resin composition containing an epoxy compound serving as a curing component and an imidazole-based latent curing agent capable of curing the epoxy compound through an addition reaction is widely used as such an anisotropic conductive paste 41.